Art of separating oil in refrigeration systems



Nov. 2, 1937. N. H. GAY

ART OF SEPARATING OIL IN REFRIGERATION SYSTEMS I Filed April 4, 1936 Sheets-Sheet 1' Norma] H Nov. 2, 1937. -N.H.GAY 2,097,725

ART OF SEP AT'ING "011, IN REFRIGERATION SYSTEMS. 7

Filed April 4, 1956 2 Sh'eets-Shet 2 .A/armrz. 15 5a,

Patented Na. 2, 1931 ART OF SEPABATING OIL IN REFRIGERA- TION SYSTEMS Norman H. Gay, Los Angeles, Calif. Application April 4, 1936, Serial No. 12,828

- 17 Claims.

Thisinvention relates to the art of. separating oil from refrigerant in a refrigerating apparatus of the type including a condenser and a still or evaporator, and employing 011 in the course of the refrigerating cycle; and is a continuation in part of my copending application Serial No. 709,864, filed February 5, 1934.

One of the features of the present invention is the utilization of the "gas lift" effect in the separator as a means of lifting the oil during the separation.

Another feature of the present invention is the provision of an oil separating apparatus in association with the conduit line for conveying 'hot refrigerant liquid to the evaporator, so that a heat exchange occurs for rectifying theoil and cooling the hot high-pressure refrigerant;

Another feature of the present invention is the provision of a refrigerating apparatus employing a plurality of compressors in conjunction with a single condenser system and a single evaporator system, with a separating apparatus connected between the condenser and the evaporator, and serving for returning the separated and rectified oil to the several compressors.

One form of practicing the present invention is shown on the accompanying drawings, in

which:

Figure 1 is a diagrammatic 'view showing the connection of the parts of the refrigerating system.

Figure 2 is a side elevation of the separating device. a

Figure 3 is a vertical sectional view through the separating device, on a larger scale.

Figure 4 is an end view of the separating device. a a

In the drawings, a plurality of compressors Cl, 02, are illustrated diagrammatically as provided with individual pressure conduits Ill for delivering hot compressed gas into the condenser K which is illustrated of shell type, the gas being delivered above the normal liquid level therein.

The bottom of the condenser K is provided with a receiver structure KR having a hot liquid delivery pipe ll opening the'relnto at a low level, and through which the hot condensed refrigerant liquid flows through a king valve l2 into a connection ii at the top oflthe separator structure R which is illustrated as separate from the condenser and cooler.

Afterpassing through a jacket of the separator R, aswill be described hereinafter, this liquid flows from the outlet connection I30 through a conduit llrfiid the shut-off valve 15 to an intermediate point of the height of the scale trap l6, from which it escapes at the top by a conduit i1 and passes through the valve i8 which is controlled by a float l9 within the float valve housing FV, and then passes by conduit 20 and the shut-off valve 2| to the expansion valve EX, and thence by conduit 22 into the evaporator EV at a point thereof corresponding to the normal liquid level therein; so that this relatively warm refrigerant liquid is delivered adjacent thetop surface of the liquid already contained in the evaporator EV. Evaporation occurs in the evaporator (likewise illustrated as of shell type), and the gases are withdrawn therefrom bythe suction lines 23 back to the individual compressors, usually with, the inclusion ofa shut-off valve 24 adjacent each compressor. The floatvalve hous ing W is provided with the'gauge glass 25 and the usual shut-off cocks, and the interior'of the housing is connected by conduits 26 with the bot- 20 tom of the receiver structure KB. and with a point of the condenser K which is well above the maximum liquid level therein. r This provides a circuit by which the refrigerant is circulated with compression at the compressor, condensation at the condenser, pressure release at the expansion valve, evaporation in the evaporator, and a return to the compressor. The separator R is shown in Figs. 2 and 3 to comprise an outer jacket 30 and an inner jacket 3i which are spaced apart to receive a plurality of helical tubes 33 having a continuously upward course and which are of such diameter that the bubbles of refrigerant gas formed therein will operate to provide a gas lift" for the liquids contained in these individual tubes. ,As the diameter of these tubes must be relatively small, owing to l the small quantity of refrigerant remaining with the oil in the final stages of rectification, these tubesare referred. to herein as small tubes. The inner jacket 3| is provided with a closing bottom ring 34 which seals this jacket 3| to the discharge connection 35, through which the rectified oil is finally discharged from the separator. This tube 35 passes through the closing member 33 which seals the lower end of the outer jacket 30, and through which the lower ends of the small tubes 33 project in sealed relationship so that they open into a bottom chamber 31 formed by the closing member 36, the peripheral wall 33, and the bottom sealing wall 39 which likewise is 1 sealed to the discharge connection 35. Communication with this lower chamber 31 is provided by-a conduit 40.

The annular space between the jackets 30 and 55 v u receives the hot refrigerant liquid through the connection it (Figs. 1 and?!) adjacent its top.

and discharges this liquid, after a cooling there:

oi, through'the bottom connection its into the; conduit H as described above.

The upper end of the inner jacket ii is sealed tea ring 4! which in turn is sealed to the drain." 1 -'conduit 42 leading from the upper chamber 41. This drain conduit 421s sealed to the upper clos-jing member 44 through which pass the upp r ends of the tubes 33 in sealed relationship; The upper end of conduit 42 is preferably at a slightly lower level than the upper ends of-the tubes 33.

f the individual tubes 33 are preferably extended parallel to the axes of the jackets and SI, so that they-facilitate the assembly of parts and j provide a space adjacent the upperand lower end rings 34 and 4|,sojthat the spaces between these rings-and the respective closing members I, and

44 may operate as headers for receiving the liq uid entering from the connection "and for-"the liquid to bedischarged through the connection I811.- -For this purpose, as shown in Fig. 4, it is" preferred to have the connections II and Isa directed tangentially with respect tothe inner jacket 3|.

I As shown in Fig. l, the evaporator EV is pro vided with conduits 50, 500 which respectively open thereinto just at the liquid level therein and at the; bottom of the same, and .are

individually controlled by valves 5|, Si so'that one or the other, or both, of these conduits may be employed according to the relative gravity of the oil compared with that of the refrigerant.

Thus if the oil is lighter than the refrigerant liquid,- it is withdrawn through the conduit while if the'oil is heavier than the refrigerant liquid, it is withdrawn through the conduit too.

It will be understood that the liquid thus withdrawn is not pure oil but contains a considerable proportion of liquid refrigerant therein, and inmany instances oontalnsmore liquid refrigerant than it does on. This mixture is then delivered through the conduit Ill into the bottom'chamber' 31 of the separator, and thus passes into the individual tubes 33 and moves upward therein to flll the same to a level equivalent to the level of refrigerant in the evaporator EV. This normally is below the floor of the top chamber 4 3.

The incoming hot refrigerant liquid from connection it, however, bathes these tubes and effects a heat transfer through the tube walls so that evaporation occurs of the contents within these individual tubes. It will be noted that thehottest refrigerant liquid encounters the tubes near their tops where they contain the smallest quantity of refrigerant liquid compared with the oil content; while the countercurrentiflow causes the relatively cooler refrigerant liquid to encounterthe cold incoming mixture from conduit 40 which contains the highest proportion of refrigerant liquid. Thus there is a continuous distillation along the length of the individual tubes without extreme pulsations occurring by a high degreeo heat transfer at any particular point along the length of the individual tube. 1 Further, by. having these tubes of helical shape, the upward new isfiretardedand sudden pulsations in "the systemare avoided.- A Y The street of vaporationis to ereate a:

bubbles or foam so that the gas which passes the conduit" or We back to the separator. Tii majo'r quantity of the oil, however, is detained .within the upperchamber 4i and flows down spaceof theinnerjacket-SI whose wallslikewise beingheatedby'j-the hot-incoming liquid reextension 35a (Fig. I under .control'of the valve}; 62. and the oil drain header 5!, which extends I acrossthecompressors and is connected-thereto: by the individual supply lines- 84 having/the con troi valves" and thus operating' as oil open. 4, I i For safety i .dling the'plant, cnecompressor Cl .is' provided with a pump-out connection "having. a control.

has a drain connection 64 at the bottom ofitsx from the conduit ll atJa point closely adjacentv fess lift in the" individual tubes which-causes.

them todischarge a mixture of gas and" oil into. J",- the upper 48. this oil usuallycontain-fl :ing a small further: quantity of refrigerant. This upper chamber 43 permits a rapid breaking of the through the conduit" into the. top of the evaporator and thence is withdrawn by the individual suction conduits 23, is substantially free from oil. .Any entrained oil. carried alon however creates no difficulty "as it is held in the evapo-vrator and sooner 'or later again passes throng ward through the conduit 42 intothe 'interio frlge'rant'i from; connection It, so that there' is slow further distillation in this chamber. with the upward escape of-- gas bubbles into the 119m!- chamber 43.. The oil thusis rectifledin the structure It so that the-substantially pure oil,'--frce from liquid refrlgerana collects at the bottom of the inner Jacket 3i and can be withdrawn from through the conduit connection '35 and its connections between {the .jevel'ai] compressors;- which are in operation andhave their-r-veives- II valve 6! for clearingthescondenser K, and a -i similar'pump-out connection" with'a'valve flfor clearing .the evaporator.- The'condenserjK.

receiver KB, and the cooler has a drain co'nnec tion 65 at its bottom. The oil header 53 has a, I 1 connection 66 by which the oilmay be charged or drained'and suction applied. h

An emergency by-pass connection 61 extends the reservoir KR and through a control valve. 88, and is connected to the conduit-22 and thus with the evaporator EV at the low pressure side of theexpansipn valve 2:2. This permits a quick release of the liquid refrigerant in the receiver 55 KB, if so desired. Similarly, the conduit i4'is.

provided with a branch 69 having a valve 1| therein; and leading to the conduit 22.. so that I the liquid may-be passed from the separator outlet directly to the evaporator without passing 60 through the scale trap id or the float valve 'II and expansionvalve E8.

A relief connection through valve H and conduit 12 connects the top of the condenser K with, the suction conduit 41 from the separator to per 65- mit relieving gases which are present at the top of the condenser. 1

It is obvious that the invention is not limited solely to the form of construction shown, but that it may be modified in many ways within the scope of the appended claims. 7

Iclaim: 1. A separating apparatus for refrigerating plants, comprising inner and outer jackets and walls sealing the space between the Jackets and 75 2. A separatingappaIatus, pl ts comprisi municating with said chambers 'andibclnzj located in the space between thejacketa aninlet 'connectionior hot refrtgerant mun at-thcupi end of theI jacket --spacm an-foutlct connection j for refrigerant liquid; at rthelower" end 0! the jacket space, v I

n and liquid 'refrigerant into lower chamber, n suction: connection from. theupper -chamber, and an .oil at v i the iowerend ofthe a e made; tmmheflma the the m wanna, an inner n 35cm? b61118, incommunicatio wit Q chamber at a low level'thereof remnants walls sealing the space between of said jacketsrafplurality of small tubes 'com- 7 municatingj with said chambers'and being locatied in thezspace rbetween the inn'er'and outer,

' I jachetspat lease niajorfportionslof said tubes being helical," an inlet connection for hot "refrigerant liquid atthe'xupper end of jacket space, an outlet connection for refrigerant liquid at the lo'we'rendof' the jacketspacaa connec -1 1 none as I refrigerant into' the; lower chamber, a I suction connection from the-upper. 'chamber,- and. an oil withdrawalconn'ection atgthe lower'end'qfthe space inside thefinner jacket, the upper end of the space-within said inner'lacket beingin come municationf withth levelthereoif.

efuppergchamber 'at alow 'a. a se 1 e tsp-data at; semenplant'ahcomprlsing concentric inner' and outer and being locatedin'the space between the inner I each tube being directed substantially. parallel to the axis of the jackets and theintermediate jackets andwalls sealing the. between. the

jackets .and providing chambers at the upper and, lowerends of said jackets, a plurality of small tubes communlcatingwithsaid chambers and outer jackets, the upper and lower ends of portions of each tube being helical and nesting with the other tubes .within the jacket space, an inlet connection for hot refrigerant liquid at the upper end of the jacket space, an outlet connection for 'refrlgerantliquid atthe lower end oi the jacket space,"a connection for delivering a mixture of oil and liquid refrigerant into th y lower chamber, a suction vconnection from the upper chamber, and anoil withdrawal-connection at the lower endof the space inside the inner jacket,

the upper end of the space within said inner jacket being in communication with the upper chamber at a low level' thereof.

4. A separating apparatus for refrigerating plants, comprising concentric inner and outer Jackets and walls sealing the space between the jackets and providing chambers at. the upper and lower ends of said jackets, aplurality of small tubes communicating with said chambers and being located, in the space between the inner and outer jackets, theupper and lower ends of each tube being directed substantially parallel to the axis of the jackets and the intermediate portions of each tube being helical and nesting with the other tubes within the jacket space, said walls and the axial portions of the tubes providing headers at the upper and lower ends of the jacket space. an inlet connection for hot refrigerant liquid at the upper end of the jacket se an outlet connection for refrig a comiectlon for delivering a mix-* pressunconduit means connecting the a wfloat inn 'snd, outer lo k t ass is t v V the'jac ketsy andl* providing chambers at the upper andlowerxends 'cated above the level delivering a' jrnixture of oil and liquid v,

' evaporator,

nected in circuit, a

- the inner jacket, the upper end of the space within said inner jacket being in communication with theupperchamber at a low level thereof.

same in valve ,in a said conduit means between the condenser andevaporator and responsive "to the liquid level in the condenser, and a separator comprising a jacket and a plurality of tubes therein, the space within the "jacket-being arrangedin the conduit means between the condenser and the evaporator so that hotliquid refrigerant flows said tubes, the upper ends of thetubes being loof 7 liquid in the evaporatorvand the lower end of the separator beingbelow the lowest point'of the evaporator, an inlet connection to the lower endsof said tubes for delivering a mixture of oil and liquid refrig:

Ferant from said evaporator into the tubes, said tubes operating by gas-lift induced by the vaporization of refrigerant therein from the upper ends of the tubes to the evaporator forreturning gaseous refrigerant to the and an oil collectlonmeans for receiving .oil irom the upper ends of said tubes.

6. In a refrigerating plant including a compressor, a condenser, and an evaporator connected in circuit, a separator comprising a plurality of small tubes enclosed by jacket means having its space connected in the circuit between the condenser and the evaporator, means for introducing" a mixture of oil and refrigerant liquid from the evaporator at the'lower ends of the tubes, 'a suction connection from the upper ends of the tubes for returning gaseous refrigerant toward the compressor, and means for collecting oil' issuing from the upper ends of said tubes and returning it to the compressor.

7. In a refrigerating plant including a compressor, a condenser; and an evaporator conseparator comprising a pluralltyof small tubes enclosed by jacket means having itsspaceconnected in the circuit between the condenser and the evaporator, means for introducing a mixture of oil and refrigerant liquid from the evaporator at the lower ends of the tubes, a suction connectionerant toward the compressor, means forgcollecting oil issuing from tubes, and a. valved pressurerelief connection from the bottom of the condenser for passing liquid refrigerant directly to the evaporator.

8.- In a refrigerating plant pressor, a condenser and an evaporator connected in circuit, a heat exchanger disposed between the condenser and evaporator to cool the liquid refrigerant, and extending above and be-'- low the level 011 the liquid in the evaporator, means for withdrawing a mixture of oil and refrigerant liquid by gravity from the evaporator to the heat exchanger and volatilizing the refrigera'nt liquid therein to produce the cooling including a com-g f 5. A refrigerating apparatus having a high level evaporator, alow level condenser, a comover the outsides of by the heat ofsaid hot refrigerant liquid, an outlet connection as I the upper ends of said efl'ect in said heat exchanger, the refrigerant gas operating by gas-lift effect to move the mixture in said exchanger, meansfor returning gaseous refrigerant to the evaporator, and means for collecting theoil from the evaporated mixture.

9. In a refrigerating plant including a compressor,-a-=-condenser and an evaporator connected in circuit, a heat exchanger dispoud between the condenser and evaporator to cool the liquid refrigerant and having a first conduit means for the liquid refrigerant to be cooled and a second conduit means for receiving a mixture of oil and refrigerant liquid from the evaporator for producing the said cooling effect therein and to return gaseous refrigerant to the evaporator, the inlet of said second conduit means to the exchanger being below the normal oil level in the vevaporator, the vaporization of refrigerant in said second conduit operating to provoke circulation therethrough by the gas-lift effect, and means for withdrawing oil from the gaseous refrigerant at a high level in said second conduit.

10. In a refrigerating plant including a compressor, a condenser, and an evaporator connected in circuit, a heat exchanger including a first chamber through which liquid refrigerant is passed from the condenser to the evaporator and a second chamber for a cooling fluid, said second chamber extending above a d below the liquid level in the evaporator, condui means connecting said second chamber to the evaporator at a high level thereof and also at the oil i evel therein for delivering by gravity a mixture 9f oil and refrigerant'liquid to said second chamber and returning gaseous refrigerant to said evaporator, and an oil trap connected at the upper end of said second chamber, the gas-lift effect of' evap orated refrigerant in said second chamber being effective to'move the mixture of oil and liquid refrigerant toward and to move at least the oil into said trap. V

11. In a refrigerating plant including pressor, a condenser and an evaporator connected in circuit, a heat exchanger disposed between the condenser and evaporator and including a collection chamber and first conduit means in heat exchange relation with a second conduit means for the refrigerant liquid .on its way to the evaporatorsaid first conduit means extending above and below the liquid level in the evaporator and being in free communication with said collection chamber at the topof the latter, a gas exhaust connection from the upper ends "of the first conduit means and-said collection chamber, and further conduit means for passing a mixture of oil Iand liquid refrigerant by gravity from the evaporator into the lower end of said first conduit means.

12. A separating apparatus for refrigerating plants comprising an enclosing casing, a plurality of small tubes located within said casing and each having a continuously upward course, header means at the top and bottom of the casing in communication with the corresponding ends of each of said tubes, means for introducing a warm circulating medium into the casing space sured to the circuit, aseparator comprising jacket means comprising inner and outer walls and having the annular space between saidwalls connected in the circuit between the condenser and the evaporator, a plurality of small tubes extending upwardly in said annular space, means for introducing a mixture of oil and refrigerant liquid from the evaporator atthe lower ends of the tubes, a suction connection from the upper ends of the tubes for returning gaseous refrigerant toward the compressor, the space within said inner wall having communication with the upper ends of the tubes and constituting acollection chamber for oil, said collection chamber being warmed by heat transferred through said inner wall.

15. A separating apparatus for a refrigerating plant comprising inner and outer walls providing an inner space and an annular space, a plurality of tubes having a continuously upward course in the said annular space, upper and lower header means in communication with the ends of said tubes, means for introducing a warming medium at the upper end of the annular space and for exhausting said medium at the lower end of said annular space, and an oil drainage connection from the upper header into said inner space.

16. A separating apparatus for refrigerating plants, comprising inner and outer walls spaced horizontally apart to provide an inner space and an annular space, separate and closure means for said walls, a plurality of tubes having a continuously upward course within said annular space,

upper and lower header means in communication with the ends of said tubes, said header means including the closing means for the outer wall, inlet and exhaust connections for a warming medium in communication with said annular space, and an oil drainage connection from the upper header into said space.

17. A separating apparatus for refrigerating plants, comprising horizontally spaced inner and outer walls providing an inner space and an annular space, a plurality of tubes having a continuously upward course within the annular space, inlet and outlet connections for a warming medium in communication with said annular space, header means at the upper and lower ends of the outer wall for closing the same and providing NORMAN n GAY. 

